Commutator



i 9, 394m R. P. LQVELAND 2,207,594

COMMUTATOR Filed Sept. 21, 1959 Inventor @Tt 1 i Loveiand,

CPR

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Patented July 9, 1940 PATENT OFFICE COMMUTATOR Robert P. Loveland, Fort Wayne, Ind., assignor to General Electric Company, a corporation of New York ApplicationSeptember 21, 1939, Serial No. 295,934

17 Claims.

' My invention relates to commutators for dyna mo-electric machines and methods of making the same."

An object of my invention is to provide improyedand simplified commutator constructions. Another object of my invention is to provide improved methods of making commutators.

Further objects and advantages of my invention will become apparent and my invention will be better understood from the following description referring to the accompanying drawing, and the features'of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this specification. In the drawing, Fig. 1 is an end view of my improved commutator, partly broken away to illustrate the relative arrangement of the conducting and insulating portions thereof; Fig. 2 is a sectional side ,view taken along line 2-2 of Fig. 1 Fig.3 is a-side'elevation of one of my improved commutator segments; Fig. 4 is a plan view of the commutator segment shown in Fig. 3; Fig. 5 1 an end view of another embodiment of my invention, partlybroken away to illustrate the relative arrangement of the conducting and insulating portions of the commutator; Fig. 6 is a side elevation of the commutator shown in Fig. 5 partly in section to illustrate the relative arrangement of the commutator segments with respect to the commutator support; Fig. '7 is a plan View of a sheet metal member from which the commutator segments of Fig. 5 are made; Fig. 8 is an end view of a modification of a sheet metal member, as shown in Fig. '7, having a heavier central segment portions; and Fig. 9 is a sectional side view of a further embodiment of my invention.

Referring to the drawing. I'have shown in Figs. 1 and 2 a simplified commutator construction comprising a plurality of commutator segments in which are made from sheet metal punchings, as shown in Figs. 3 and 4. These sheet metal punchings are formed as strips including the central commutator segment portion ID and end portions or prongs I I on each end thereof. These prongs II are provided with anchoring heads l2 at the ends thereof and are punched in the form of a fiat strip, as shown in Fig. 4, and then are bent at right angles to the central segment, portion H], as shown in dashed line in Fig. 3. A plurality of these strips are assembled to form a complete commutator, and each strip is secured to a preformed annular insulating element l3 which may be made of any suitable material such as hard fibre. The prongs H at each end of the segments iii are clamped securely about the two outer edges of the annular insulating member l3 and a plurality of these segments are arranged in circumferentially spaced apart relation about the outer peripheral surface of this insulating member. In order to provide a suitable support for the commutator and to insulate the commutator segments from the support, I provide a mass of moldable insulating material M, which may be made of any suitable material such as a phenolic condensation prodnot, and mold this material about the inturned end portions or prongs II and between the inner sides of these prongs and a metal supporting sleeve l5. In order further to insure the rigid support of the commutator upon the sleeve I5, I also mold the insulating material l4 around the outer ends of the prongs II and between the sleeve 15 and the insulating annular member or sleeve l3. In forming this complete assembly, the moldable insulating material I4 may extend about the outer surface of the commutator segments ID, as shown by the dashed lines [6 in Figs. 1 and 2, and this excess insulating material is then removed by turning or grinding the outer surface of the commutator to provide metallic outer contact surfaces to the commutator segments H) which are concentric with respect to the mounting or supporting sleeve l5. Furthermore, the sleeve 25 may be omitted or removed. and the molded insulating portion l4 mounted directly upon a motor shaft.

In Figs. 5 and 6 I have shown a modification of my improved commutator construction which provides a completed commutator very similar to that shown in Figs. 1 and 2. In manufacturing this commutator, a sheet metal blank of substantially rectangular shape is punched with a plurality of notches, slots. or indentations IT on each of two opposite parallel sides thereof. These slots l7 form a plurality of transversely extending prongs l8 separated by the slots 17, as shown in Fig. '7. and if desired. the prong portions I8 may be made of lesser thickness as compared to the central or contact portion 24 to provide a heavier wearing bar section, as shown in Fig. 8. This sheet metal blank is formed into a substantially cylindrical shape about a preformed annular insulating sleeve member l9. which is arranged adjacent the inner ends of the notches or slots [7, and the prongs 18 are firmly clamped about the outer ends of this insulatin member. In order properly to support the commutator, I provide a metal mounting or supporting sleeve 29 which is arranged within the inturned end portions or prongs I8 and is secured thereto and insulated therefrom by a mass of moldable insulating material 2|, formed of any suitable insulating material such as a phenolic condensation product. This insulating material 2| is molded about the inturned end portions or prongs l8 and between the inner ends of these prongs and under the insulating sleeve IE! to insulate completely the substantially cylindrical sheet metal element and the prongs l8 thereof from the supporting sleeve 20. vided with a knurled or roughened surface 22 adjacent the central portion thereof about which the insulated material is molded in order more firmly to secure it in position upon this supporting sleeve. After the insulating material 2| has been molded the outer peripheral surface of the commutator is turned down or ground to provide a peripheral metallic contact surface thereon which is concentric with the supporting sleeve 20. The original surface of the commutator is indicated by dashed lines 23 in Figs. 5 and 6. Individual commutator segments 24 are formed by extending thenotches or slots I! completely transversely across from side to side, so as to sever the cylindrical surface of the sheet metal member between each adjacent slot II. This may be done conveniently by milling spacing grooves or slots 25 through the sheet metal member and partially into the annular insulating member l9. As in the arrangement shown in Figs. 1 and 2, this provides a commutator wherein the commutator segments are secured in position upon a preformed insulating sleeve and are mounted upon a supporting sleeve by another insulating member which secures the commutator segments in assembled relation about the first mentioned annular insulating member. If desired, however, the inner sleeve 20 may be omitted or removed and the insulating portion 2i mounted directly on a motor shaft.

In Fig. 9 I have shown a further modification of my improved commutator construction, wherein a plurality of commutator segments 26 are arranged in spaced apart relation about the outer peripheral surface of a preformed annular insulating sleeve member 21. Each of these segments 26 is provided with end portions or prongs 28 at both ends thereof clamped about the end portions of an insulating sleeve 27. A second insulating sleeve or bushing 29 is arranged in contact with the inner surface of the prongs 28 and provides a press fit between the prongs 2B and the sleeve 29 in order to secure the segments in assembled relation about the sleeve 21. The insulating sleeve 29 also may be provided with a radially extending collar 30 which engages a portion of the ends of prongs 28 on one end of the commutator. This sleeve 29 is formed of any suitable insulating material such as a phenolic condensation product or a fibre sleeve which is securely mounted upon a metal supporting sleeve member 3|. In order to insure the concentricity of this commutator, the outer peripheral contact surface thereof is turned or ground down from its original size, as indicated by dashed line 32, to the size shown in full lines in this figure. Ths commutator construction provides substantially the same completed structure as that shown in the other figures, and the commutator segments may be made as separate punchings as in Figs. 1 to 4 or as a sheet metal stamping and subsequently cut apart as in Figs. 5 to 8. In addition, it is cheaper to manufacture, as

The sleeve 20 is pro-' it does not require the molding of the mounting insulating member between the supporting sleeeve and the inner side of the inturned prongs 28. As in the other constructions, the inner sleeve 3| may be omitted if desired.

While I have illustrated and described particular embodiments of my invention, modifications thereof will occur to those skilled in the art. I desire it to be understood, therefore, that my invention is not to be limited to the arrangements disclosed, and I intend in the appended claims, to cover all modifications which do not depart from the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A commutator including a preformed annular insulating element, a plurality of commutator segments arranged in circumferentially spaced apart relation about the periphery of said annular element, each of said segments having an inturned portion securely clamped about a portion of said insulating element, and means including a second insulating element arranged in contact with a surface of said inturned segment portions for retaining them in assembled relation.

2. A commutator including a preformed annular insulating element, a plurality of commutator segments arranged in circumferentially spaced apart relation about the periphery of said annular element, each of said segments having an inturned portion securely clamped about a portion of said insulating element, means including a second insulating element arranged in contact with a surface of said inturned segment portions for retaining them in assembled relation, and a supporting sleeve secured within said second insulating element.

3. A commutator including a preformed annular insulating element, a plurality of commutator segments arranged in circumferentially spaced apart relation about the periphery of said annular element, eachof said segments having an inturned portion of lesser thickness than the remainder of said segments arranged in securely clamped relation about a portion of said insulating element, and means including a second insulating element arranged in contact with a surface of said inturned segment portions for retaining them in assembled relation.

4. A commutator including a preformed annular insulating element, a plurality of commutator segments arranged in circumferentially spaced apart relation about the periphery of said annular element, each of said segments having an inturned portion securely clamped about a portion of said insulating element, and moldable insulating material arranged about a part of said inturned portions of said segments.

5. A commutator including a preformed annular insulating element, a plurality of commutator segments arranged in circumferentially spaced apart relation about the periphery of said annular element, each of said segments having an inturned portion securely clamped about a portion of said insulating element, a moldable insulating material arranged about a part of said inturned portions of said segments, and a supporting sleeve secured within said moldable insulating material.

6. A commutator including a preformed annular insulating element, a plurality of commutator segments arranged in circumferentially spaced apart relation about the periphery of said annular element, each of said segments having an inturned portion securely clamped about a portion of said insulating element, and means including an insulating sleeve arranged in contact with a surface of said inturned segment portions for retaining them in assembled relation.

7. The method of making a commutator which comprises arranging an electrically conductive member about the outer peripheral surface of an annular insulating element, clamping an end of the conductive member about a part of the annular insulating element, and placing another insulating element in contact with a part of the clamped end portion of the electrically conductive member. to retain it in assembled relation.

8. The method of making a commutator which comprises arranging an electrically conductive member about the outer peripheral surface of an annular insulating element, clamping an end of the conductive member about a part of the annular insulating element, placing another insulating element in contact with a part of the clamped end portion of the electrically conductive member to retain it in assembled relation, and arranging a supporting sleeve within said last-mentioned insulating element.

9. The method of making a commutator which comprises forming a plurality of strips of electrically conductive material, arranging the strips of conductive material in spaced apart relation about the outer peripheral surface of an annular insulating element and forming inturned portions adjacent an end of each strip in clamped engagement about a part of the annular insulating element, and placing another insulating element in contact with the inner sides of the inturned portions of the strips to retain them in assembled relation.

10. The method of making a commutator which comprises forming a plurality of strips of electrically conductive material, arranging the strips of conductive material in spaced apart relation about the outer peripheral surface of an annular insulating element and forming inturned portions adjacent an end of each strip in clamped engagement about a part of the annular insulating element, and placing a moldable insulating material about a part of the inturned portions of the strips.

11. The method of making a commutator which comprises forming a plurality of strips of electrically conductive material, arranging the strips of conductive material in spaced apart relation about the outer peripheral surface of an annular insulating element, clamping each end of each strip about a part of the annular insulating element, and placing a moldable insulating material about a part of the inturned portions of these strips.

12. The method of making a commutator which comprises forming a plurality of strips of an electrically conductive material, arranging the strips of conductive material in spaced apart relation about the outer peripheral surface of an annular insulating element, clamping an end of each strip about a part of the annular insulating element, and placing a moldable insulating material about a part of the inturned portions of the strips and between the inner surface thereof and a supporting sleeve.

13. The method of making a commutator which comprises forming a plurality of notches along an edge of a sheet metal member to provide a plurality of transversely extending prongs separated by these notches, arranging the prongs in clamping engagement about an edge of an annular insulating element, placing another insulating element in contact with the inner sides of the prongs to retain them in position, and extending the notches transversely of the sheet ietal member to sever it into a plurality of separated segments.

14. The method of making a commutator which comprises forming a plurality of notches along two opposite parallel edges of a sheet metal member to provide a plurality of transversely extending prongs on each respective edge thereof separated by the notches, clamping the prongs along each edge of the metal member about an edge of an annular insulating element, placing another insulating element in contact with the inner sides of the prongs to retain them in position, and extending the notches transversely of the sheet metal member to sever it into a plurality of separated segments.

15. The method of making a commutator which comprises forming a plurality of notches along an edge of a sheet metal member to provide a plurality of transversely extending prongs separated by the notches, forming a substantially cylindrical element of the sheet metal member, arranging an annular insulating element within the cylindrical member, arranging the prongs of the cylindrical member in clamping engagement about an edge of the annular insulating element, extending the notches in the cylindrical element to completely sever it into a plurality of segments, and placing another insulating element in contact with the inner sides of the prongs to retain the segments in assembled relation.

16. The method of making a commutator which comprises forming a plurality of notches along two opposite parallel edges of a sheet metal member to provide a plurality of transversely extending prongs on each edge separated by the notches, clamping the prongs along each edge of the sheet metal member about an edge of an annular insulating element, placing a moldable insulating material about the prongs to retain the sheet metal member in position and also between the inner surface of the prongs and a supporting sleeve, and extending the notches in the sheet metal member to sever it into a plurality of segments.

1?. The method of making a commutator which comprises forming a plurality of notches along two opposite parallel edges of a sheet metal member to provide a plurality of transversely extending prongs on each edge separated by the notches, clamping the prongs along each edge of the sheet metal member about an edge of an annular insulating element, placing a moldable insulating material about the prongs to retain the sheet metal member in position, and extending the notches in the sheet metal member to sever it into a plurality of segments.

' ROBERT P. LOVELAND. 

